The present disclosure generally relates to laser material processing. More specifically, the disclosure relates to laser beam containment means and methods.
Lasers and laser systems are generally divided into four major classifications according to their potential to cause biological damage to the eye or skin. One such classification system is established by the American National Standards Institute, commonly referred to as ANSI. The classification standards are known as the ANSI Z136 standards.
The purpose of these classifications is to warn users of the hazards associated with the laser relative to the accessible emission limits. These limits are based on laser output energy or power, radiation wavelengths, exposure duration, and cross-sectional area of the laser beam at the point of interest.
Referring to the ANSI classifications, a classification of 1 means that a laser is safe under all conditions of normal use. This means the maximum permissible exposure (MPE) cannot be exceeded when viewing a laser with the naked eye or with the aid of typical magnifying optics (e.g. telescope or microscope). A class 1 laser cannot emit laser radiation at known hazard levels (typically continuous wave: CW 0.4 μW at visible wavelengths). Users of Class I laser products are generally exempt from radiation hazard controls during operation and maintenance (but not necessarily during service). Since lasers are not classified on beam access during service, most Class I industrial lasers will consist of a higher class (high power) laser enclosed in a properly interlocked and labeled protective enclosure. In some cases, the enclosure may be a room (walk-in protective housing) which requires a means to prevent operation when operators are inside the room.
Most lasers used for material processing are Class 4 lasers. A class 4 laser is the highest and most dangerous class of laser, including all lasers that exceed the Class 3B AEL. By definition, a Class 4 laser can burn the skin, or cause devastating and permanent eye damage as a result of direct, diffuse or indirect beam viewing.
A Class 4 laser can be installed in a workcell that is certified as a Class 1 enclosure. However, a Class 1 enclosure must guarantee that the light emitted from the Class 4 laser stays within the enclosure or is safe outside of the enclosure under all conditions of normal use.